The v201607 will remain the default version for reports until the week of November 28, 2016. This gives you enough time to verify your scripts and make sure they work with the latest report version.

If you use API versioning in your reports, you need to modify your code to use v201609:

var report = AdWordsApp.report(query {
apiVersion: 'v201609'
});

If you don't use API versioning, no code changes are required. Your reports will continue using v201607 for now, and switch to v201609 when we make v201609 the default version the week of November 28, 2016.

If you have any questions about these changes or AdWords scripts in general, you can post them on our developer forum. - Mike Cloonan, AdWords API Team